Although it can be applied to any desired fiber composite components, the present invention and the problems on which it is based are explained in more detail below with reference to two-dimensional stringer-stiffened carbon fiber reinforced plastic (CRP) components, for example skin shells of an aircraft.
It is generally known to stiffen CRP skin shells with CRP stringers in order to withstand the loads occurring in the aircraft sector with the lowest possible additional weight. In this respect, a distinction is drawn essentially between two types of stringers: T and Ω stringers.
The cross section of T stringers is made up of a base and a stem. The base forms the connecting surface with respect to the skin shell. The use of skin shells stiffened with T stringers is widespread in aircraft construction.
Ω stringers have something like a hat profile, its ends being connected to the skin shell. Ω stringers may either be adhesively attached in the cured state to the likewise cured skin shell, or be cured wet-in-wet at the same time as the shell. The latter is desired, because it is more favourable from technical aspects of the process. However, supporting or molding cores are necessary for the wet-in-wet production of skin shells stiffened with Ω stringers, in order to fix and support the dimensionally unstable semifinished fiber products in the desired Ω shape during the production process. Skin shells with Ω stringers have the advantage over T stringers that they allow better infiltration during an infusion process for introducing a matrix, for example an epoxy resin, into the semifinished fiber products. Infusion processes are less costly than other known methods for producing fiber composite components, such as the prepreg process for example, because this allows the use of lower-cost semifinished fiber products.
However, there is the problem with the production of Ω stringers that the material used at present for the supporting or molding core is cost-intensive and can only be removed with difficulty after the forming of the Ω stringers, with the result that the material remaining in the stringers contributes adversely to the weight of the fiber composite component, and consequently to the weight of the aircraft. Furthermore, it is problematic that the material remaining in the stringers contributes adversely to the overall weight of the aircraft.